1780
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
for different types of the model grounds is remarkable, while
the difference in
K
0
values is not so high.
5 CONCLUSIONS
Thick lines in Figure 5 (R-pipe) and Figure 6 (F-pipe) show
the analytical results. The analytical
are null. Comparison be-
tween analytical and experimental results indicates that the ana-
lytical results in Figures 5 and 6, as well as those shown in Fig-
ure 3, are consistent with the experimental results except for
exceptional cases. It should be noted that the measured
in the
experiment are always close to be null, which conformed to
=0 in the analysis. However, the current design standards us-
ing the seismic deformation method based on the spring model
assume that
acting on the pipe surface govern the seismic be-
havior of buried pipes. This contradicts with the results obtained
in the experiment and analysis, revealing that the current seis-
mic design standards are misleading.
The validity of the proposed continuum model for interpretation
of the seismic behavior of buried pipes as soil-pipe interaction
was confirmed by experiment. It can be concluded, therefore,
that a basic theory for seismic design of buried pipes, instead of
current seismic design based on problematical spring models,
was provided by this study.
6 REFERENCES
Moore I.D. 1989. Elastic buckling of buried flexible tubes
A review
of theory and experiment.
Journal of Geotechnical Engg.
,
ASCE
,
115(3), 340-358.
One of the analyzed cases being inconsistent with the ex-
periment is the case when R-pipe was buried in S0D-ground.
There are two areas in which the analyzed
are negative (ten-
sion). As soil cannot resist tension, separation between the pipe
and soil must have occurred in the experiment. This separation
must have generated redistribution of earth pressure, resulting in
smaller
and
M
in the experiment than in the analysis. This in-
terpretation was validated by a FEM analysis in which the sepa-
ration at the pipe-soil interface was considered.
Tohda J. and Mikasa M. 1986. A study of earth pressure acting on bur-
ied pipes through theory of elasticity.
Journal of JSCE
376(
Ⅲ
-6),
181-190.
Tohda J., Li L., and Yoshimura H. 1994. Analysis of the factors in earth
pressure and deformation of buried flexible pipes through centri-
fuge model tests,
ASTM STP1222 Buried Pipe Technology
, 180-
194.
Tohda J., Yoshimura H., and Li L. 1997. Mechanical behavior and de-
sign of buried pipes as a soil-structure interaction,
Proc. of the 14th
ISSMFE
, 1049-1052.
Another exceptional point of inconsistency between the
analysis and experiment is the specific concentration of
measured at two measuring points 18
or 36
apart from the top
and bottom of F-pipe (cf. Figure 6). Its magnitude increases
with the increase in
N
in any case. The concentration points of
exactly reversed when the ground was deformed to the right-
hand side. The analysis showed that the soil elements close to
the surface of F-pipe at the concentration points of
were sub-
jected to compressive mean stresses, whose magnitudes were
around two times greater than those in R-pipe. On the other
hand, the magnitudes of deviator stresses at the corresponding
points were similar in F-pipe and R-pipe. It was supposed,
therefore, that compression of the soil close to the concentration
points of
in F-pipe must have strengthened the rigidity of the
soil irreversibly during the iterative simple shear in the tests, re-
sulting in the specific concentration of
on F-pipe.
Tohda J. 2001. A study of buckling behavior of buried pipes through
theory of elasticity.
Journal of JGS (Tsuchi-to-kiso)
49(4), 19-22.
JSWAS (Japanese Sewage Works Association). 2006. Earthquake-
resistant measures guidelines and commentary of sewer facilities.
Tohda J., Yoshimura H., Inoue Y., and Mukaichi H. 2010a. Centrifuge
model tests and analysis on seismic behavior of sewer culverts.
Journal of JGS (Tsuchi-to-kiso)
58(2), 18-21.
Tohda J., Yoshimura H., Ohsugi A., Nakanishi K., Ko H.Y., and Wallen
R.B. 2010b. Centrifuge model tests on dynamic response of sewer
trunk culverts,
International Conference on Physical Modeling in
Geotechnics (ICPMG 2010
), 651-656.
Ohsugi A., Nakanishi K., Tohda J., Maruyoshi K., Yoshimura H., and
Inoue Y. 2011. Stability against seismic loading, of sewer trunk
culverts severely deteriorated after renovated by lining methods
with discrete pipes and spirally wound pipes,
Proc. of the 46
th An-
nual Conference on Geotechnical Engineering
,
JGS
, 1459-1460.
-20
(kN
·
m/m)
-20
-10
0
0
0
0
-10
M
10
10
0.1
0
0
0
0
0.1
0.1
0.1
(MPa)
0
0
0
0
-10 (kN
·
m/m)
-20
M
10
10
10
0.1
0
0
0
0
0.1
0.1
0.1
(MPa)
-10
0
0
0
0
-10
-20
-20
(kN
·
m/m)
M
10
10
0.1
0
0
0
0
0.1
0.1
0.1
(MPa)
-20
(kN
·
m/m)
-20
-10
0
0
0
0
-10
M
10
10
10
10
0.1
0
0
0
0
0.1
0.1
(MPa)
1
2
5
10
Analyzed
Measured
N
,
(a) S0L-ground,
H
/
D
=1
(b) S0L-ground,
H
/
D
=2
(d) S0D-ground,
H
/
D
=1
(c) S16L-ground,
H
/
D
=1
Figure 6. Comparison between experimental and analytical results (F-pipe).
